Emerging Time-Resolved X-Ray Diffraction Approaches for Protein Dynamics

Proteins guide the flows of information, energy, and matter that make life possible by accelerating transport and chemical reactions, by allosterically modulating these reactions, and by forming dynamic supramolecular assemblies. In these roles, conformational change underlies functional transitions. Time-resolved X-ray diffraction methods characterize these transitions either by directly triggering sequences of functionally important motions or, more broadly, by capturing the motions of which proteins are capable. To date, most successful have been experiments in which conformational change is triggered in light-dependent proteins. In this review, I emphasize emerging techniques that probe the dynamic basis of function in proteins lacking natively light-dependent transitions and speculate about extensions and further possibilities. In addition, I review how the weaker and more distributed signals in these data push the limits of the capabilities of analytical methods. Taken together, these new methods are beginning to establish a powerful paradigm for the study of the physics of protein function.

Automated summary

Proteins play crucial roles in guiding the flow of information, energy, and matter in life by accelerating transport and chemical reactions, modulating these reactions, and forming dynamic supramolecular assemblies. Conformational change is fundamental to functional transitions, and time-resolved X-ray diffraction methods have been successful in characterizing these transitions. This review focuses on emerging techniques that investigate the dynamic basis of function in proteins without native light-dependent transitions, and discusses potential extensions and future possibilities. Additionally, the review examines the challenges posed by the weaker and more distributed signals in these data, pushing the limits of analytical methods. Overall, these new methods are establishing a powerful paradigm for studying the physics of protein function.